There is a need for compactly structured beam addressable information storage disk drive systems capable of fitting within the half height format of a personal computer drive bay. The problem of achieving this objective is complicated somewhat by the fact that beam addressable storage disks are rigid plastic disks many times the thickness of flexible ("floppy") disks commonly used as removable storage media for personal computers. Moreover, such disks are generally encased in protective hard shelled cartridges that add to the bulk of the disk assembly that must be accommodated in the drive system. Unlike conventional high capacity magnetic disk drive systems employing small magnetic sensor heads positioned at the end of an arm in direct or semi-direct contact with a non-removable magnetic disk, a magneto-optical drive system must accommodate a relatively bulky optical read/write head to scan the data tracks on the disk. Such a system has the highly desirable advantage of allowing the use of removable disk storage media but at the expense of requiring the use of considerable space devoted to the scanning read/write head and associated control components.
Thus, in order to minimize the space within the drive system devoted to loading and unloading the disk cartridge, it has been proposed to utilize a system in which the cartridge is loaded and held in its own plane within the drive system with the spindle drive being translated from a non-operational position to an operational position in which the spindle is engaged with the disk central hub. While this arrangement frees up space in the drive that would otherwise be required to accommodate translation of the cartridge to bring the disk into engagement with a fixed spindle, it puts a premium on proper initial positioning of the cartridge and its disk relative to the spindle axis. Accordingly, it is desirable that the cartridge be provided with automatic powered loading, at least during the final phase of the loading, to assure proper positioning each time a cartridge is inserted into the drive.
A related consideration is that when the cartridge is loaded in its operational position within the drive system, it is generally inaccessible to the user. As a consequence, means must be provided to assist in ejecting the cartridge from its position internal to the drive, at least to the point at which it can be readily grasped by the user and manually removed to complete the unloading process. Because of the limited space available to accomplish this initial unloading step, it is highly desirable that the same powering mechanism used to load the cartridge be used for the unloading step as well.
Accordingly, it is an object of the invention to provide a compact disk cartridge positioning mechanism for an information storage disk drive system.
It is another object of the invention to provide a compact, "powered-in" cartridge loading mechanism for a system of the type described that assures proper positioning of the cartridge and its associated disk each time the cartridge is loaded.
It is a further object of the invention provide a compact cartridge unloading mechanism for a system of the type described that utilizes the same drive components that are employed for "powered-in" loading of the cartridge.
It is still a further object of the invention to provide a motor actuated cartridge loading and unloading mechanism for a system of the type described that occupies a minimum of space in the cartridge receiving cavity.
It is yet another object of the invention to provide a powered cartridge loading and unloading mechanism for a system of the type described that operates from a single motor actuator that is also used for other load functions in the disk drive system.